Genetic abnormalities*, chimeras

 ( genetic abnormalities)

• Susceptible botanical family(s)

• Production areas affected :

• Organs attacked : 

• Symptoms :
  • leaf discolorations affecting one to several leaves: contiguous yellow to white sectors, more or less well extended, are visible on the leaf blade (figure 1);
  • discolorations sporadically affecting stem and fruit;
  • leaf development leading to a more or less marked deformation of the leaf blade.

• Cause : local malfunction of the tissues of the limbus, the synthesis of chlorophyll is more or less inhibited. This genetic anomaly must be considered as a curiosity without consequences for the culture. Indeed, in the majority of cases, a very small proportion of plants is affected. It is to be classified as a physiological disease.

• Diagnostic clues :
  • in the majority of cases, one or a few plants are affected;
  • the symptoms normally appear early, and only on the cultivated species;
  • the expression of the symptoms of certain genetic diseases can be influenced by the temperature and/or the genotype cultivated.

• Possible confusion : viroses or phytotoxicities in particular. Note that this condition is in no way transmissible to surrounding plants.

• Remedies :
• no particular measures to be taken;
• eliminate the affected plant if desired.

* many genetic mutations or chromosomal aberrations (in the constitution of the chromosomes or in their number) are responsible for other symptoms, in particular changes in the shape of the leaflets and leaves in vegetables, even on their other organs (stems, fruits ). In the presence of such phenotypic aberrations, often occurring in isolated plants, with symptoms manifesting early and sometimes dramatically, making them wrongly fear the worst for their crop. Associated with more or less "crumpled" leaves or leaflets, rolled up in relation to their axis or their plane, with thicker tissues, with floral sterility, etc., the affected plants must be considered as curiosities without consequences. Note that these other genetic anomalies are in no way transmissible to surrounding plants.